To a semiconductor integrated circuit, an electric source voltage depending on an operation voltage thereof needs to be supplied. For example, as illustrated in FIG. 6, a semiconductor integrated circuit 50 is connected to an electric source output part and a feedback voltage input part of an external direct-current/direct-current (DC/DC) converter 60. The DC/DC converter 60 outputs an output voltage V2 as an electric source voltage to the semiconductor integrated circuit 50. In the semiconductor integrated circuit 50, the electric source voltage supplied to a load 70 is detected and fed back as a feedback voltage Vfbk to the DC/DC converter 60. The DC/DC converter 60 controls a circuit operation so as to stabilize the feedback voltage Vfbk at a standard voltage Vref1. Note that a circuit configuration of the illustrated DC/DC converter 60 is one example and is well known, and thus, description thereof is omitted.
In the example of FIG. 6, in the semiconductor integrated circuit 50, the electric source voltage supplied to the load 70 is detected, and this detected voltage is fed back as the feedback voltage Vfbk to the DC/DC converter 60. The feedback voltage Vfbk is not adversely affected by a wiring resistance R3 inside the semiconductor integrated circuit 50. For this reason, based on the feedback voltage Vfbk, the DC/DC converter 60 can stabilize the electric source voltage supplied to the load 70, without being adversely affected by the wiring resistance R3.
One example of a technique related to such the control of the electric source voltage is described in reference 1 (JP2008-197892A). In this technique, a series regulator includes an electric power adjustment unit adjusting input electric power and outputting the adjusted electric power to a load side, and an adjustment control unit detecting an output voltage and controlling the electric power adjustment unit. The series regulator controls input electric power input to the electric power adjustment unit, depending on an output current to the load side.
Further, another example of the technique related to the control of the electric source voltage is described in reference 2 (JP2015-88652A). In this technique, a semiconductor integrated circuit includes an electric source generation circuit, a function module, and a capacitor. The capacitor is arranged on the outer side of the electric source generation circuit. Further, one electrode of the capacitor is connected to an output portion of the electric source generation circuit, and another electrode is connected at a standard potential. The function module connects the electric source generation circuit via the capacitor. To the function module, an electric source voltage generated by the electric source generation circuit is supplied as an operation electric source voltage.
Furthermore, reference 3 (JP2010-507289A) describes one example of a technique for controlling a current, as the technique related to the control of the electric source voltage. In this technique, a current limit value of user setting is detected, and depending on the detection signal, a current is limited.